With development of mobile communications, increasingly higher user requirements on high-speed data transmission, and increasingly diversified demands of users, modern mobile communications is developing towards a direction of multi-frequency multi-mode. An upgrade speed of mobile communications device is gradually accelerating. However, it is increasingly difficult to acquire available site resources in an urban area. Therefore, multi-frequency multi-mode operation becomes one direction of future development for base station antennas. A multi-frequency multi-mode base station antenna also provides a more effective solution for site sharing of mobile communication operators, and provides the benefits of smooth upgrade of a live-network device and being green and energy-saving.
For the multi-frequency multi-mode base station antenna, namely, a multi-frequency array antenna, one same antenna needs to include multiple antenna subarrays that can work on a same frequency band or different frequency bands. However, limited installation space and broadband operation of the antenna subarrays bring new challenges to antenna design.
In the prior art, a multi-frequency array antenna, as the one shown in FIG. 1, may be used. The antenna is arranged in the following order: a high frequency subarray 11, a low frequency subarray 12, and a high frequency subarray 13. Although a size of the multi-frequency array antenna is compact, and the two high frequency subarrays have relatively consistent electrical performance indicators, a gain of the low frequency subarray is relatively low.